WASHINGTON -- Russia's new ambassador to the United States, arriving at a time of heightened tensions between the two countries, says Moscow is ready to take "concrete" steps to improve ties with the United States.

Russian state-run news agencies reported that Ambassador Anatoly Antonov presented his credentials to U.S. President Donald Trump on September 8, just days after the latest chapter in a raging tit-for-tat diplomatic dispute between Moscow and Washington.

"I have just been received by President Trump to hand over my credentials. On my part, I told him that we hope for improvement in relations between our countries," Antonov said, according to Russian media. "The atmosphere was good, constructive, and friendly."

U.S. officials have not yet commented on the ambassador's meeting with Trump.

The United States on August 31 ordered the closure of Russia's consulate in San Francisco and trade annexes in Washington and New York.

The U.S. action came after Moscow ordered the United States to reduce its personnel at diplomatic facilities in Russia to 455, which represented a cut of about 755 staff members.

Antonov, a veteran diplomat who is under sanctions by the European Union for his role in Russia's interference in Ukraine, did not speak directly to the diplomatic row, only saying that "we want our relations to be trusting, mutually respectful, equitable, and certainly mutually beneficial."

Before his meeting, the ambassador said that "it's highly regrettable the Russian-U.S. relations are going through this upheaval now, right at the moment when international problems we could resolve together with the United States are piling up."

During his 2016 presidential campaign, Trump had repeatedly expressed wishes for better relations with Russia and often praised President Vladimir Putin.

But, even prior to the latest diplomatic dispute, several issues have prevented much progress in bilateral ties.

The U.S. Congress enacted legislation tightening sanctions against Moscow for its alleged interference in the U.S. presidential election, its annexation of Ukraine's Crimea Peninsula, and its support for separatists in eastern Ukraine.

The United States and Russia have also disagreed on potential solutions to the civil war in Syria and in dealing with North Korea's banned nuclear and ballistic-missile programs.

In addition, the former Russian ambassador to the United States, Sergei Kislyak, was at the center of controversy for his contacts with members of Trump's campaign team during the 2016 campaign and the transition following his win in November.

Kislyak, 66, ended his term on July 22, paving the way for the appointment of Antonov, who has served in both the Foreign Ministry and Defense Ministry.